Stoking apparatus



Nov. 6, 1945.

c. E. SHAFFERV ET AL STQKING APPARATUS Filed March 15, 1940 I 4 Sheets-Sheet 2 INV M om. m mfi o a n EH. R i a ma W Nov. 6, 1945. 'c. E. SHAFFE-R' ET AL 2,383,294

STOKING APPARATUS 10 BY gzwcmh,

Q ATTORNEY.

Nov. 6, 1945. c. E. SHAFFER ETAL I 2,383,294

STOKING APPARATUS Filed March 15, 1940 4 Sheets-Sheet 4 I TRAVEL OF MEMBER 59 ga e,

. 50 rd firs/752, dz.

' ATTORNEY.

Patented Nov. 6, 1945 STORING APPARATUS Chester E. Shaffer, Jersey City, N. 1., and Albert Boyd Fisher, J r., Wilkinsburg, Pa., assignors, by mesne assignments, to Koppers Company, Inc., a corporation of Delaware Application March 15, 1940, Serial No. 324,048

' 6 Claims. ((ll.- 110 -45) The present invention'relates to the domesticheating art and pertains more especially to novel improvements in apparatus and their auxiliary equipment for employing solid fuels, and more particularly coke derived fromvcoal, in the automatic supplying of heat to furnaces forming a part of the heating installations of dwellings;

smaller buildings, and the like.

A primar object of the present invention is the provision for domestic-heating installations of a unitary system that is responsive to a predetermined requirement and is adapted automatically to withdraw solid fuels from. a near-bystorage and to deliver them to the fuel-bed of a heating furnace and to remove ashy combustion-residues from both the fuel-bed and the furnace-hearth.

of the installation in particulate form before hav-' ing opportunity to fuse into large-sized clinker, thefeatures of apparatus of the said unitary system being all co-operatively co-ordinated to perform the stated functions in a manner to assure continuous uniformity .Of flow of the required fuel into the heating installation and the removal of combustion-residues therefrom without detrimental segregation of such materials interfering, in any part of the unitary system or of the heatthe consistent co-operation of the several regulated apparatus notwithstanding variations of fuel and of required heat delivery.

The invention has for, further objects such other improvements and such other operative advantages or results as may be found to obtain in the apparatus hereinafter described or claimed.

In the accompanying drawings forming a part of this specification and showing for purposes of exempliflcatio i a preferred apparatus in which the invention'may be embodied and practised but a without limiting the claimed invention specifically to such illustrative instance or instances.

Fig. 1 is a general schematic view in plan of heating apparatus embodying features of the unitary system of the present improvement for emplaying solid fuels in domestic furnaces;

Fig. 2 is a view in elevation of the apparatus shown in Fig. 1;

Fig. 2a shows an enlarged fragment of Fig. 2; Fig. 3 is a sectional view taken along the line 111-111 of Fig. 1 and showing details of construction oflthe fuel-conveyor and storage bin of the instant improved unitary system;

ing installation, with consistency of performance over protracted periods. I

Another object of invention is the provision of a unitary system that is operative by a. single driven member to perform the above-stated functions and has features of apparatus whose opera-' tions are individually regulable within the system to promote a continuous consistency of performance and results irrespective of reasonable variations in such factors as the size of the employed solid fuels, their ash content, rates of combustion, and the like. v

More specific objects of the present improvement are the provision, in a unitary system for the stated purpose, of: a solid-fuel storage bin that is adapted uniformly and automatically, and independently of the level of fuel therein; to deliver its entire contents on conveyor means arranged to carry such fuel regulably in a horizontal path and without degradation to regulable stoker means; a stoker that isparticularly adapted to resist the abrasive action of such fuel as coke; and a furnace grate that is regulably oscillable about a vertical axis to impart greater or lesser movement to the pieces of fuel comprising the fuel-bed, thereby optionallyeither to increase Fig. 4 is a partial plan view, parts broken away, of the furnace-grate, the stoker, the conveyor means for feeding fuel to the latter from storage and the actuating means for operating the present improved system for employing solid fuels in domestic furnaces;

Fig. 5 is a side elevational view of Fig. 4 and showing the adapter-member whereby fuel moved from the storage bin by the conveyor is introduced into the underfeed stoker;

or diminish the effect of said gratev in the removal of ashes from the fuel-bed; the several regulationmeans being adapted effectively to maintain Fig. 6 is a sectional view taken along the line VIVI of Fig. 5 and showing the cross-section of the under-feed tube adjacent its change of axial direction; h

Fig. '7 shows an enlarged fragment of Fig. 4 with the fuel-conveyor, however, disposed substantially at right angles to its relative position illustrated in the latter said figure;

Fig. 8 is an enlarged view of the adapter-member of Fig. 5 that serves communicably to connect for purposes of fuel-flow the Stoker and the fuelconveyor of the system and also shows the damper arrangement for eliminating draft through the stoker and into the fuel bed during such times as e ,the system is idle;

Fig. 9 is a front view of the damper arrangement or Fig. 8: e

Fig. 10 is a section taken alongthe line'X-X of Fig. 4; I

Fig. 11 is a plan view of the feed-tube of the stoker member with parts broken away to show the same parts in each of the views of the drawmgs.

Referring now to the drawings: the unitary system of the present improvement for using such solid fuels -as anthracite, bituminous coal, pitch coke, and the like, and more particularly coke derived from coal, in the automatic supplying of heat to domestic heating installations essentially comprises: an improved arrangement of bin for storing and supplying a quantity of fuel; an improved conveyor for transporting fuel therefrom in a horizontal path to a stoker; an underfeed stoker; an improved grate to support the fuelbed in the furnace; means for automatically removing ash from the furnace-hearth; a fuel-bedlevel control; and suitable regulable connections between the above-mentioned features of apparatus and an electric motor whereby said apparatus can be all co-operatively actuated by the latter to provide for the combustion of that amount of solid fuel which is necessary to deliver uninterruptedly and automatically the quantity of heat required to maintain a given space at a predetermined temperature.

. The fuel bin 20 is of a capacity to provide adequate Storage of-fuel for a preferred period and, as clearly shown in Figs. 1, 2, is formed with a hopper-like bottom comprising the pair of inclined surfaces 2|, 2|, that are disposed along its lengthwise dimension, and also the inclined surfaces 22, 23, that are arranged transversely of the former respectively adjacent the outlet and its opposite end of the bin. The said surfaces 2|, 2|, do not meet on the bins median but rather stop short thereof, as shown in Fig. 3, at the vertically-extending walls of a trough-like member that forms the lowest part of the space of the bin, and all of the said inclined surfaces function as directing baliles to deliver fuel from all sections of the bin into the trough-like portion thereof. That inclined surface 22, which is located above the bin-outlet should have its lower e located at about 6 to 9 inches above the bottom of the bin-trough, such distance being regulated according to the sizes of solid fuel employed, and at. about inches inwardly from its adjacent verticalwall, thus. forming a sort of pocket l9 whereinto a portion of the bin-contents can freely flow along the bin-trough and assumeits angle of repose unobstructed by the weight of the column of fuel thereabove. In order to effect, by means of the conveying device provided for the present improvement, a uniform rate of removal of the entire contents of thebin. it has been found advantageous to incline the surfaces 22, 23, at not less than 45 degrees and the 'surfaces 2|, 2|, at not less than 32 degrees to the horizontal, depending on the nature of the material used in their construction. Tempered,

pressed-wood, such as the material Masonite. has been found in practice a satisfactory material for facing said surfaces.

The conveyor means 30 for transporting fuel in a horizontal plane between the bin and the stoker members of the unitary system of the invention comprises plate 3| that is reciprocally as clearly shown in Fig. 3. In order to facilitate' the reciprocatory movement of plate 3|, it is slidably supported above the bottom of its housing 32 on metalstrips 33 that serve as tracks. The said conveyor-housing 32 extendsfrom substantially the lower edge of directing baflle 23 the entire length of the storage-bin and to the stoker inlet. In that section thereof where the housing forms the bin-trough, its side walls are bent outward to such angle that they in effect form extensions of inclined surfaces 2|, 2|, thereby promoting the flow of fuel onto the upper surface of reciprocating plate 3|. From the bin outlet, at pocket I9, to the stoker-inlet, these'side-walls are substantially vertical. Metal-covered wooden strips 34 are aiiixed to the walls of conveyorhousing 32 and extend substantially the entire length .thereofsumciently adjacent the vertical surfaces of plate 3| to prevent wedging of fuel particles between said housing and reciprocatory plate, but are also suificiently removed therefrom to allow free movement of the latter. In effect, the wooden strips 34 form a sort of recess in which the reciprocating conveyor-plate is actuated, and have the effect of directing all fuel that flows into the bin-trough only onto said plates upper surface. By obviating any possibility. of coke jamming at its edges, they are an important feature in the successful operation of a conveyor of this type.

Beneath the reciprocatory plate 3| of the conveyor and affixed thereto at its outer end is connecting-rod 36 whereby it is actuated by the electric motor that is adapted to operate the unitary system of the invention, said connectingrod being attached to the conveyor-plate by angle-iron 31 that is itself bolted to the latter and through which the reduced and threaded outerend of rod 36 extends. as shown in the enlarged view of Fig. 2a. Lock-nuts 38 support and retain the connecting-rod in the angle-iron. Increasing or decreasing the distance between the pairs of said lock-nuts respectively serves to increase or decrease-the amount of movement made by the driven connecting-rod independently of the conveyor-plate, so that they are employable correspondingly to decrease or increase the amount of movement imparted to the conveyormounted in a sheet metal housing 32 that forms the side walls andthe bottom of the bin-trough,

and, consequently, serve as means of regulating the quantity of fuel carried from the bin during each cycle of movement of theconveyor-plate.

Solid fuels have been successfully transported on conveyor-plates, of the above-described type, that were 25 feet long; the practical limit therefore of their length is considerably above that dimension. A conveyor-plate that is 5' inches wide is capable of carrying 200 pounds of solid fuel per hour.

As will be notedin Fig- 2, the driven end of the conveyor-plate 3| extends beyond the end of the bin-trough so that in its reciprocatory motion fuel cannot be jammed between the outer edge of said plate and the walls of the trough.

That section of the conveyor housing located between the storage-bin and the stoker is provided, for purposes of cleanliness, with coverplate 33. v

Adjacent the discharge or inner-end of conveyor 30, the reciprocatory plate and the recessforming'members 34 therefor are both supported on the horizontal surface of the inlet to adaptermember 4|, that is held atop the stoker apparatus, and which serves todirect conveyed fuel downwardly'onto the actual stoking device of said stoker. Cleats- 40 amxed to the walls of the adapter-member'allow free movement of the con-' veyor-plate and assist in supporting it in a substantially horizontal plane.

Flexible finger Hi attached to the walls of adapter-member M, as shown in Fig. 4, can be moved by its associated thumb-screw to restrict or increase the free-way for fuel flowing along the conveyor-plate and thus, in addition to the described device at the outer end of said connecting-rod for limiting the motion of theconveyorplate, serves as means for obtaining fine regulation of the quantity of fuel delivered from storage to the stoker during any period. The flexible finger I of the apparatus from which the present drawings were made, comprises a fiexible plate or gate in the form of a piece of sheet metal, the upper edge of which is shown at I in Fig. 4. v

Adapter-member II, for directing conveyed fuel into the stoker apparatus, is supported in the circular inlet to the latter by means of screws 43 as shown in'Figs. and 8; in consequence of this arrangement, the adapter and its associated conveyor are pivotable around the stoker-inlet and can be thus arranged at a diversity of angles to the stoker and the furnace, a feature making it possible to employ the present improvement in places where the existing fuel-storage space is variously disposed in respect of the furnace openings. I

' As also shown in Figs. 5, 7, 8, and 9, a dampervalve 44 is installed at the inlet side of said adapter-member 4| for disestablishing' communication between the conveyor and the stoker during such times as fuel is not being introduced into the latter, thereby to prevent combustionair being drawn into the furnace through a conduit comprising the conveyor-housing and the horizontal section of the stoker casting of which .placeable liner-plates 53 that cover most of the lower part of the side walls of the tube and are conveniently formed of cast iron, hard-surfaced steel, or other appropriate material. These plates 53 are of greater thickness adjacent the fuel inlet of the stoker-tube than they are further therealong, as shown in Fig. 11, their vertical edges thus forming a sequence of ridges or offsets that have the effect of presenting to the solid fuel as it traverses the casting in the direction of the grate, tube-sections of increasing cross-sectional area which facilitate the stoking operation and tend to restrict any backward movement of the stoked fuel during the backward stroke of the reciprocatory stokerplate 5|.

Reciprocally mounted within tube-casting 52, and forming a substantial portion of its lower wall, is the stoker-plate 5| which, adjacent the the both are only partially filled with solid fuel 7 at any interval. As shown in said Figs. 8, '9,

damper-valve 44 is supportedat its top by a.

hinged arrangement to the walls of adapter ll adjacent its inlet. Fingers 45 depending from one end of the hinge-pin serves to open and close said damper-valve, said finger being automati- I cally actuated by arm 46, that is attached to and moves correspondingly with connecting-rod 36, as is evident in Figs. 5, 7, and 8 in such manner that during the forward stroke of the latter, when coke is being delivered to the stoker, the damper is opened and conversely is-closed on the return stroke of said connecting-rod. Inasmuch, as will be hereinafter set forth, connecting-rod 36 is always at the end of its back stroke when the unitary system of invention is at rest,

damper-valve Ml is in opened position only at such times as fuel is being delivered to the' stoker. Counterweights 41 are employed to close and insure a close sealing of the damper-valve.

Removable plate'48, which is attached to and forms the top of theadapter-member, supports, in the threaded hole 49, the bolt- 81 which has a lock-nut 82 and carries the principal metallic covering 33 for the working parts of the assembly- Referring now to Figs. 4, 5, and '7, the stoker apparatus incorporated in the present invention is of the underfeed type and comprises a cast-.

inlet-end of said tube-casting, is mounted on cross-head H of the driving mechanism for the unitary system and extends through a provided slit in the adjacent end-wall of said casting. At its opposite end, said stoker-plate is rigidly aflixed to the upper surface of ram-head 53, the

'said cross-head, plate, and ram-head being all arranged for reciprocatory movement as a unit. The shelf-like ridges 52 shown in Fig. 10 on the inner walls of the tube-casting form a track for the stoker-plate during its reciprocatory movements. f r v Removably mounted in the lower wall of the stoker-tube adjacent its upward bend,'is the fingar-bar 6 l which is retained in position by means of its attached lug that slidably fits into a corresponding-opening in the wallsof the stokertubel As clearly shown in Figs. 5 and 10, ramhead 59 is formed with a median groove which 3 permits it to move freely backwards and forwards over the said stationary finger-bar which serves the function of aiding in the support of the vertical column of fuel above it during the backward stroke of the ram-head.

Lugs 54 55, formed integrally with the stokertube casting have threaded holes containing bolts ing 52' having a relatively extended, horizontal section that, beneath the fumace-grate, terminates in substantially a right-angle bend on the upper surface of which there is supported a removable extension-ring 63, the vertical. section 56 whose heads serve as feet for said casting and whereby the stoker can be levelled. e

That lower wall-portion of the stoker-tube, adjacent the point where the stoked fuel undergoes a. sharp change of direction, is naturally subjected to heavy abrasive action by the fuel. It has therefore been found expedient, for lengthening the operative life of a stoker-tube, to form its wallsin this part of extra thickness of metal, as shown in Fig. 6; in the same figure, there is also clearlyfillustrated rib I33 that is cast integrally with the stoker-tube walls and which,

in combination with the hereinabove described finger-bar GI and also the adjacent offsets formed at the termini of liner-plates 53, assists in supporting, above the normally only partially filled horizontal section of the stoker-tube, that vertical column of fuel which is about to be elereciprocatory ram-head 59.

The upper edge of extension-ring 63 i flanged and presentsa smooth surface wh'ereon there is rotatably supported, by means of a co-acting groove, the grate 60 of the unitary system of the substantially a horizontal planeand its slotted perforations 98, that extend through the body thereof for the removal of ashes from and for the admission of combustion air to the fuel bed, are arranged in groups according to a barred pattern wherein each has at least one slot sub- 7 stantially radially disposed whereas the remainder are in parallelism therewith.

Directly beneath the grate for which it can function as means to prevent tipping of the former in the event of unequal loading, or the like, but operatively independent thereof, is the ash-ring 80 which is supported by radial brackets 85 that are themselves supported at their inner ends on the outer walls of extension-ring Ash-ring 80 is formed of arc-like sections bolted together, the ends of such sections having slot-like openings that permit adjustment of its overall diameter, so that its periphery can be made substantially equal to that of the grate or be increased somewhat thereover. This feature of extensibility of said ash-ring is of special importance in that it permits the employment of a grate of some standardized dimension in an existing furnace having a fire-box of which the internal diameter is so much greater than that of the grate that otherwise excessive leakage of ash and fuel would take place in the peripheral space therebetween. The closing of this peripheral space by the ash-ring is susceptible of further refinement by supporting thereon, during the installation of the apparatus, aseal 84 formed from an asbestos cement, or the like.

After ashy combustion-residues have passed through the slots 98 of the grate, they are re moved from the furnace-hearth, according to the present invention, by means of a pair of reciprovated into the fuel-bed by the movements of the present unitary system for employing solid fuels in the automatic supplying of heat to domestic heating installations, is arranged for actuation in response to fuel requirements of the fuel-bed to keep the same at a constant level. Means for accordingly actuating the unitary system are provided by an'improved fuel-bed-level control which comprises gem'culate rod llll to which is aflixed at its lower end a truncated metal body I02, preferably formed from such resistant alloy as N1- Resist, or the like, that is in constant contact with the upper surface of the fuel-bed, said rod being pivotally mounted on a bracket for movement in a vertical plane, so that the member I02 can easily follow small changes in the level of the upper surface of the fuel-bed. counterweight I03 is adjustably mounted on the outer end of rod llll thereby increasing its ease of movement and sensitivityto changes in the fuel-bed level and also functioning to prevent the said rods own weight causing its sinking below the surface of the bed. Adjustably affixed to the said genlculate rod where it extends through switch-box I04,

there is an electrical switch, preferably of the Mercoid type, that is included in the circuit for driving electrical motor H2 whereby the unitary system of invention is actuated. The said switch is disposable to open or close said circuit when the upper surface of the fuel-bed has re- 40 erative through speed-reducer I I3, crank-arm H4,

catory bars 9| which are pivotally secured to that cross-head 94 depending from the post 99 that is, itself aflixed to the under side of the reciprocatory feeder-plate 5| and with which it moves backwards and forwards in unison. Adjacent their opposite ends, said bars 9| are slidably held in guides 93 therefor which are spaced apart a distance greater than that obtaining between the said bars pivots on their cross-head. During their reciprocatory movement the ash-removal bars are thus provided with some lateral as well as a lengthwise movement, the former said movement serving to clear a path through the ash-heap which is. wider than the bars, so that any of the ashes falling onto their upper surfaces can be moved therealong and out of the furnace-hearth without being brushed off by adjacent material of the ash-pile.

The opening to the furnace-hearth is surrounded with a tightly-fitted metal plate 92 thereby to prevent uncontrolled inflow of air through said opening to the grate. Ashes extracted'from the furnace-hearth, by the movemen't'of the ash-removal bars, drop from their surfaces into ash-pit 95 and into a therefrom removable container, if preferred.

its embodiment shown in the drawings, the

and the single driving-rod or lever I I5, all of said members being mounted on the basal casting lil. Pivotally attached to lever H5 and adapted to be reciprocally moved thereby is cross-head H to which is bolted the one end of stoker-plate 5| that reciprocates inside of stoker-tube 52.

All the driven features of apparatus, thatis, conveyor member 3|, Stoker-plate 5|, ash-bars 9| and'grate 80, are arranged to communicate directly or indirectly with the said driven crosshead ll. Viewing Fig. 4 from that end thereof adjacent the actuating motor, there is observed at the right-hand side of the cross-head H a thereto afllxed arm containing an extended obtuse-angled slot 6 which terminates at its upper end in a short transverse slot. By means of the illustrated bolt that can he slid along said slot H6 and secured at any preferred position therein,-link H1 is pivotally secured to said crosshead and serves as a connecting arm whereby reciprocatory motion of the cross-head is utilized to reciprocate the two cranks H8, disposed at right angles to each other, about their own pivot,

- which is supported in the bracket l2| attached to the lower side of the adapter-member 4|. In the apparatus from which the present drawings were made, the two cranks I I8, shown at right angles to each other in Fig.. 4, are, as indicated therein, adjustable to any angle, about their own pivot, so that when the angle of approach of the the fuel conveyor-plate 3|. The particular shape of obtuse-angled slot H6 and the adjustable an-.

gle between cranks H8 makes it possible to dispose conveyor-plate 3| at a wide range of anglesof-approach tothe stoker inlet and yet to employ the motion of member II for operating the conveyor-plate to feed the 'stoker.

Operatively connected with the opposite end of cross-head H is the train of co-operative devices whereby the furnace-grate 60, is, according to the intent of the invention, made adjustably rotatable about its vertical axis accordingly as there is required in the co-ordinable system a greater or lesser removal of ashy residues, and the like, from the fuel-bed during any period of combustion. Within linear slot 12 of the cross-head, the efiective length of said slot, as is clearly visible in Fig. 7, being simply regulable by means of a screw bolt 13 that is adapted for movement longitudinally thereof, the pin 19 is adapted to slide freely and independently of the cross-head a distance determined by and regulable according to the accorded space between the end of said bolt I3 and its adjacent slot-end and the both of which surfaces are adapted to engage said pin at some point during respectively the backward or forward movement of the reciprocatory cross-head,

and in so doing, to move in the same direction the link H which is pivotally moveable at both its ends. Movement of said link 16 by pressure of the cross-head thereagainst effects corresponding movement of link vl that is supported on a bracket, projecting from walls of the underfeedtube, by the bolt I00 which also serves to support for movement independently of said link the ratchet 61 which is rotatable around said bolt.

Spring-actuated click-68 and pawl 69. of which the former is mounted on a pin for independent movement on lever 10 whereas the latter is similarly mounted on the above-mentioned bracket afilxed to the walls of the Stoker-tube, are so disposed in respect of the teeth of ratchet 61 that pawl 69 engages a tooth thereof during the forward stroke of the cross-head, thereby allowing" lever 10 similarly to move about pin I00 independently of the ratchet and the click 68 to advance in the direction of pawl 69 a number of teeth that is regulable bythe effective len th of slot 12, and during the backward stroke of the cross-head, click 68 under the influence of. its actuating spring is arranged to engage the adjaclockwise direction. During backward movement of'thenross-head, pawl 69 slides over the .of the ratchet always in a counterclockwise direction. During its rotation around pin I00, the ratchet carries with it linkl'ldmounted thereon by pin' 78 and about which said link is rotatable. At its opposite end, the link 15 is rotatably attached to one end of the centrally-pivoted lever 65 on either end of which an adjustable leverrod 16 is pivotally mounted, the opposite ends of said rods 16 being also pivotally mounted on shoulders'll that are cast integrally with grate 80 on its lower surface where they are disposed along a diameter and whereby said grate is pro-' vided alternately with a clockwise and counterclockwise movement ina horizontal plane.

Rotation of ratchet 6] moves link 15 in alternation forward and backward thus respectively I pushing and pulling that portion of member 65 to which it is attached and thereby causing said member to oscillate on its pivotal mounting and move the grate member alternately in opposite directions in a horizontal plane.

According to the present invention, the total movement of the grate in any one direction is accomplished in sequences of stepwise movements whose lengths are variously adjustable, thereby enabling the householder to increase or diminish the amount of agitation, incidentally imparted to the fuel-fed, in accordance with the combustion results he wishes to effect. with an individual fuel. This feature of adjustability of grate-movement is of important advantage for promoting the automatic delivery of heat over protracted periods because it permits either a regulable removal of combustion-residues'from the grate and, in consequence, the maintenance of a constant rate of consumption of combustible notwithstanding changes in the ash content of the employed fuels, or; in the case of any particular fuel, a removal of ash from the fuel-bed that can be either increased or decreased to respectively enhance or diminish accessibility of combustion air to the burning fuel and correspondingly alter the rate of consumption of its combustibles. This is all simply and easily'effected by suitable adjustment of screw-bolt I3 to regulate the effective length of slot 12 of crosshead II, which in turn controls the number of teeth of the ratchet over which click 68 passes before becoming engaged for the backward stroke of the cross-head.

or ash particles lying adjacently thereabove tends, in consequence of their changing angle of incidence in respect of surface irregularities of such "materials, to provide said particles with rotational movement around their own axes in addition to that motion which is contributed by the "grate itself. Such rotational .movement isof cent ratchet-tooth so that both ratchet-and the lever 10 are simultaneously moved in a countercourse most pronounced near the grate periphery where the ash content of the fuel-bed tends to be the highest and therefore the greatest agitation of the fuel-bed is needed to remove the n ash suiliciently rapidly therefrom to prevent its 1 fusion into large size clinker. To the lower surface of any such clinker as does form on the top of the grate, the said changing angle of incidence with which a successtion of slots comes into contact therewith tends, assisted by.the

weight of the fuel-,bed' thereabove; to shear the clinker into fragments capable of passing.

through the'grate-slots and being discharged from the installation by means of ash-bars 9|. The facility with which the apparatus of invengrate-slots and the resultant special movement contributed by it to the fuel-bed, in combination with the reg-inability of the length of the steps with which the grate is moved between its limits of travel. 7

As hereinbefore mentioned the unitary system of the invention is, as shown in the drawings, adapted for actuation by novel means for maintaining the fuel-bed at a predeterminable level,

said means being arranged to close or to open an electrical circuit that includes'motor 2 respectively at such times as the upper surface of said fuel-bed has sunk below or been stoked to reach a preferred level. The electrical circuit, wherein said-driving motor is included, comprises a novel arrangement of mercury switches whereby the motor, subsequent to a period of operation, comes to rest only at such times as connecting-rod H is at the end of its backward stroke, so that said motor will always be started when it is under the least load and damper-valve 44 is always in closed position when the motor is at rest, as will be now described by reference to the drawings and, in particular, to Fig. 12.

Mounted on basal casting III of thestoker apparatus is switch box I3I that contains a Mercoid switch which is itself supported on rotatable finger I32, said finger being under the influence of a spring member that always returns it, when moved therefrom, to a pre-arranged position and .carries with it the Mercoid switch which, in the said cross-head, finger; I32 and its associated switch are returned to the. reverse position by the spring attached thereto. Connected in parallel with the Mercoid switch in box I3I is a similar switch that is contained in switch-box I04 and is arranged for movement, by the upward and downward movement of fuel-bed-level control I III, between positions adapted to open or close the electrical circuit to motor II2 respectively as the fuel-bed is stoked to reach a preferred level or sinks therebelow.

The connection in parallel of the two Mercoid switches of members I04, I3I, thus provides for the delivery of power to the driving motor at all times save when both switches are simultaneously in a position to open said-circuit, and

by its means power continues to be delivered to the motor, even after that switch of the fuel-bedlevel control has opened the circuit in its included branch line, until driving-rod II 5 is at the end of its backward stroke when both switches and the motor-circuit will be in open position until member I02 again sinks with the fuel-bed level and moves the therewith communicating switch of- I04 to close the circuit to the motor.

This feature whereby driving-rod 5 cancome to rest only at the end of its backward stroke assures, upon its restarting, that motor II! is always under the *least possible load, thereby, at

a source of power, and a power-line switch.

The working parts of the assembly are all encased in a sheet-metal covering to enhance its appearance and protectits working parts. Above adapter-member II, a portion or said covering is formed as a removable cover-plate 83 that provides ease of access to the several mechanical features.

. The co-operation of the various elements comprising the unitary system of the present invention and the importance and merit of the adiustable co-ordinable features provided therein for adapting it to solid fuels of varying characteristic and to divers requirements of heat can behest appreciated by a description of its operation while tracing the path of fuel from its storage bin onto the fumace-grata. In the following description the term -forward" will be employed to designate motion of the various parts toward the furnace and conversely the term return will be used to indicate motion in the opposite direction.

Let it be assumed that combustible of the fuelbed on the'furnace-grate has been burned to such point that member I02 of the fuel-bed-level control has sunk below a predetermined level, thereby so moving theMercoid switch of switch-box I04 as to establish a, flow of electrical current from the power lines to the system' driving-mo tor I I2. The motor causes driving-rod I I5, which is positioned at the end of a return stroke, to move forward carrying with it the cross-head II. In'its forward movement, said cross-head, by means of the hereinabove described train of apparatus connected therewith, effects similar movement of fuel-conveyor plate '3I and of stoker-plate 5| and also of th link 14 which moves click 58 in a clockwise direction around ratchet 51, the latter being held motionless by pawl 59, a number of teeth determinable by'that effective length of linear slot I2 made available by the existing setting of adjustable screw-bolt I3. At the end of its forward stroke, driving-rod H5 is caused to move in the return direction by crank-arm II4 which in turn causes members 3|, 5|, to start the return strokes of their reciprocatory motion, and when movin in'this direction, click 68'becomes engaged with an adjacent tooth of the ratchet which is thereby moved counterclockwise carrying with it lever-bar I5 which oscillates lever 85 on its pivotal mounting. Grate 60, that is oscillated by movement of the lever 65 operating through thepair of driving-bars I6, is moved in a counterclockwise or clockwise direction depending upon whether pin 18 of lever-bar I5 is momentarily respectively on'that half of said ratchet which is adjacent or opposite to the click 58. Thus, it is obvious,- that the grate memher is moved about its axis alternately a definite distance in opposite directions, and that by adjustment of the number of ratchet-teeth moved over by click 58 in the forward stroke of the crosshead, there is established the number of individual steps ascribed to said grate as it is moved between its limits of travel in either direction. The shorter the effective length of said slot I2, the greater will be the number of teeth movedover by said click, and vice versa.

In addition to the above-stated members of the unitary system, the ash-bars 9|, that are attached to the lower part of reciprocatory stokerplate 5I- are correspondingly reciprocated with thelatter, all of said members being actuated from cross-head II and in such manner that those employed for conveying materials all move path.

on the upper surface of said'plate at substantially its angle of repose. As cross-head 1] starts its. forward stroke thereby effecting similar movement of fuel conveyor-plate ii, the fuel in said pocket is carried along by said plate and thus advanced toward adapter ll of the stoker mem- .cannot be carried backward because of the resistance of the new. quantum of fuel that has flowed into the pocket I! during the plates forward travel. After a few cycles of movement of the conveyor-plate, its entire surface is covered with a shallow layer of the fuel and a small portion of which is discharged therefrom, with each forward stroke, past damper-valve '44, whereupon it falls onto the reciprocating stoker-plate 5|. The damper-valve 44 is operatively arranged to begin swinging upward to open position as the conveyor-plate 3i starts forward, and vice versa, so that said damper offers no obstruction tofiow of fuel into the stoker-tube. v

Simultaneously moving forward with the conveyor-plate is the stoker-plate BI, and fuel discharged thereon from the former is moved forward therealong in the direction of the gratev assisted by the small vertical offset twice by the By the reciprocatory motion of the ram-head, new quantities of the employed fuel are elevated into the vertically-extending section of the stoker-tube and displace that already there into the fuel-bed atop grate 60, the inflow of such fuel giving more especially the center of the fuelbed a measure of agitation and causing a sort of radial flow outward of the fuel particles already therein.

At the same time that the conveyor-plate and stoker-plate are performing their operations, the

grate is being moved either clockwise orcounterclockwise in steps of regulable distance, thereby revolving and rotating between themselves those particles of unburned "fuel andash closer the periphery of the grate, such movements causing the fine particles of ashy residues to fall through the interstices of the fuel-bed and the grate-slots 98 onto the furnace-hearth therebelow where-they are picked up on the upper surfaces of the simulthereto attached metallic block I34 hich is 10.-

cated adjacent the point where the Stoker-plate is secured to cross-head 'H, as is clearly visible in Figs.4 and 5. This oil'set functions-with each forward stroke of said stoker-plate to carry toward the grate a relatively thin layer of the" in flowing fuel.

taneously reciprocating ash-bars SI and moved out of the hearth space toward the front of the furnace whence they fall into ash-pit 95. When sufficient new fuel has been introduced into the fuel-bed to raise member I02. to a predetermined level, the Mercoid switch, in switch-box I04, will be moved to stop current 'flow therethrough whereupon, during the subsequent backward stroke of driving-rod 5, contact in the Mercoid switch or switch-box l3] will lbe broken and the system come torest until thenext demand for fuel by the level control.

From this brief description of the operations of i the co-operative features of the unitary system of the present improvement and the operative re- If the solid fuel is discharged from the con-' ,veyor into the stoker-tube at a rate in excess of that at which the stoker-plate is adapted facilely to move it. forward into the fuel-bed, said-stokerplate will jam. To obviate such circumstance the hereinabove described features for regulating the rate of discharge from the conveyor are provided. These features comprise'adiustablelocknuts 38, whereby the limits of the reciprocatory movement of conveyor-plate ,3l are determinable, as well as the flexible finger Ill, which serves to regulate that'cross-section of the conveyor space made available as a free-way for the flow of fuel therealong, By these means it is possible toeifect In consequence of the small offsets formedb member I34 andthe vertically disposed ridges of linerplates 53, 'u'rhich, as shown in Fig. 11, become progressively thinner as the grate is appreached, in combination with the bulk of the infiowing material, fuel that is moved forward on the stoker-plate is'prevented from being carried along 'on the stoker-plate'sbackward stroke and eventually reaches the lower part of the up-bend of the stoker-tube where it is picked up by the to-and-fro movement of the ram-head and elevated into the verticallyeextending section of the the solid fuel and the column of which is supported by its slight outward flare combined with sults obtainable therewith, it is evident that by means of said system it,is possible to flow a solid fuel from an adjacent storage bin onto a furnacegrate and to burn the fuel and to remove the ashy residues from the fuel-bed and the furnace so simply-and effectively that heat can be supplied to a heating installation quite automatically.

In such a' unitary system for employing solid fuels, it is however insuflicient merely to furnish co-operative features of apparatus that are adapted to perform the above-stated operations,

. because the more common of such fuels vary from one to the other in certain of their characteris-- automatic operation over a protracted period, that the component apparatus of such a system be not only co-operatively disposed but also that their individual operations be so regulably co-ordinable within the system that operative results of the one can be made consonant with that of another. For example, with fuel of a given ash content being consumed on the grate at an established rate and with a corresponding delivery thereof to the fuel-bed by the conveyor and stoker, an established angular movement of the individual steps. of the grate in its rotary motion can provide just that amount of agitation to the fuel-bed necessary to give a removal of ashes therefrom-and the gratethat is adequate to keep apace with their formation, thereby assuring good conditions of combustion andv non-formation of clinker that bright otherwise accumulate on the grate to prevent combustion air reaching the fuel and thus former whose cross-section is entirely filled with- I With such coordination of tion conditions can be thus. automatically maintained for an indefinite-period. Let it now be removable finger 6|, rib I38, and the offsets clearly shown at Y in' Fig. 11.

assumed, however. that the source of solid fuel is changed to one having a higher content of ash but that it is stilldesirable to burn the combustible of the. new at the same rate as in the previous instance. This means-that to deliver the same amount of combustible to'the grate for a given period, a larger quantity of fuel will necessarily have to be conveyed to the stoker. In the system of invention; this is simply done by increasing the amplitude of movement of conveyor-plate 3| or by retracting finger lll closer to the walls of the conveyor shell. that more ash will accumulate in the fuel-bed with fuel from this new source, it will become necessary, for the obviation of undue accumulations of such materialin the fuel-bed, to increase the amount of agitation ascribed thereto by the grate in its stepwise movement.

In the present apparatus, this circumstance is simply provided for by so moving threaded bolt 13 as to decrease the effective length of slot 12,

that determines the extent of each angular movement of the ratchet, and which in turn will increase the ang'ularity of each movement of the grate and the resultant agitation of the fuel-bed, thereby increasing the rate of ash withdrawal through the grate onto the hearth. With more rapid accumulation of ashes on the furnacehearth, ashes will be automatically piled higher on the top of the ashbars and during each cycle of their reciprocatory movement more ash will be carriedto the ash-pit. A

If, on the other hand, it is desired to employ more freely-burning solid fuel of sharply reduced ash content which makes it desirable to decrease the rate of ash withdrawal and even to allow a layer thereof to accumulate on the grate in order to reduce the natural draft, the stepwise movement of the grate can be reduced to establish such condition without altering an established setting of the conveyor; or, as is now obvious, with any given solid fuel, the extent of movement of solid fuel, an appropriate and precise adjustment.

is always establishable between the rate of fuel delivery, its rate of combustion, and the rate of ash withdrawal from the heating system, so that these factors are always in equilibrium to give optimum combustion conditions for any of.

the common solid fuels.

Those features of invention exemplified in the foregoing description which relate to the fuel conveyor 30, the fuel storage-bin and the conveyor, and the combinational aspects of the-conveyor wi th'- the operating means therefor, are

made the subject-matter of our co-pending ap-' plication for Letters- Patent of the United States, filed August 1, 1945, Serial No. 608,234; whereas those features of invention which relate to the burner-grate and operator, and their automatic si onal application, filed August 1, 1945, Serial No.

The invention as hereinabove set forth is embodied in particular. form and manner and may be In consequence of the fact variously embodied within the scope of the claims hereinafter made.

We claim:

1. A unitary domestic-heating system adapted to flow coke and coal from an adjacent fuel bin therefor to the combustion zone of 'a domestic furnace and to burn said fuel and to remove comfor reciprocating the same; said stoker floor and said ash bars being connected with the reciprocal driving means for reciprocation inunison; and separate connections between the grate and the driving means and the fuel conveyor floor v and the driving means'for oscillating movement Of the grate and reciprocation of the fuel conveyor floor on each reciprocal movement of the driving means; the connection for movement of the fumace-grate and the fuel conveyor reciprocatory floor including individually regulable means for varying-the amplitude of their movement by the drive means independentlyof the amplitude of movement of each other and of the stoker floor and of the ash 'bars on each reciprocation of the driving means. for coordination of the rates of supplying fuel to and rate of removing combustion-residues from the fuel-bed for automatic continuance of predetermined conditions of combustion in the fuel-bed irrespec- -.tive of quantity of ash in the employed fuel or of required delivery of heat bustion.--

2, In a unitary domestic-heating system adapted to flow coke and coal from an adjacent fuel by the fuels combin therefor to the combustion zone of a domestic furnace and to burn said fuel and to remove com- 'bustion-residues from ,the furnace, the combination of: a circular furnace-grate having a multiplicity of slot-like perforations mounted for oscillatory movement about a vertical axis; regulable eans for moving said grate in a succession of re able steps between its limits of travel;

an underfeed stoker for supplying solid fuel to means for operating the same, are made the subsaid grate; and means comprising a reciprocatory plate-member for delivering fuel from said fuel-bin to said stoker; and regulable means for movement of the plate member in strokes of regulable length; the regu-lable means for moving the grate and the plate-member being individ-,

ually resulable independently of each other and of the stoker.

a 3. In a unitary domestic-heating system adapted to flow'coke and coal from an adjacent fuel bin therefor to the combustion zone of a domestic furnace and to burn said fuel and to remove combustion-residues from the furnace, the combination of: a circular furnace-grate having a multiplicity of slot-like perforations and mounted for oscillatory movement about a vertical axis; re-

. ciprocal 2,888,294 means for moving the grate in a sequence of regulable steps between its limits of travel; an underfeed stoker for supplying solid from said storage qimprising a reciprofor delivering fuel the plate-member in strokes of regulable length; and a reciprocatory ash bar pivotaily supported for to extract combustionlongitudinal movement both lateral and residues from the furnace-hearth; and reciprocal driving means for the grate and and also with the stoker and the ash bar to reunison, feed plate-member each havciprocate them in for the grate and means connected with the reciprocal for the plate-member said reciprocal means ing individually adjustable means for adjusting the amplitude of their ently of each other and of reciprocation independthe stoker and ash bar.

, 4. Fuel feed-means for a domestic-heatin system adapted for burning coke and coal comprising a reciprocatory stoker adapted fuel-bed from beneath a grate during but one period of its cycle of fuel aforesaid into a ment and, in the reverse for feedin moveperiod, to return -said member to stoiring position, a driven reciprocatory member therefor, electric motor for actuating the same, a control member adapted to lie on the top of the fuel-bed and to move upwardly and downwardly with fluctuations in the electrical circuit motor andconsisting of two p arallelly-connectcircuit having means arby said control member relevel, a multiple ed circuits, the one ranged for actuation I fuel bed including said spectively to open and to close the same when the surface of the fuel-bed is stoked up to or is burned below a predetermined level, and the other circuit having othermeans whereby its circuit is opened :by said driven'reciprocatory member only when the latter has reached a preferred point in its reverse cycle of movement. so

that the driven member sequent to its retraction,

is always stopped suband at its position for and is made sensitive to the movements toward said inlet beginning a next cycle of stokin'g movement when it is under the least possible load.

, 5. Apparatus asclaimed in claim 1 and which includes means responsive to predetermined elefuel-bed and to move upwardly and downwardly therewith. said control member being provided with an adjustabiy disposed counterweight whereby it is adapted to be buoyed up-and to float lightly upon the fuel beds upper surface thereof that the regulable grate oscillations tend to main. tain within minor range; an electrical circuit including the-motor for actuating the reciprocable driving" means; for actuation by said control member respectively to open or close said circuit when the fuel-bed is stoked up to or is burned below a level predeterminable by said adjustable means.

6. Apparatus. as claimed in 'claiml and in 1 which the fuel conveyor for conveying the fuel from the adjacent iuel bin to the stoker comprises a conduitand a reciprocatory plate as the floor extending from the fuel bin to substantially the inlet of the stoker, and in which the plate is arranged to discharge fuel during its movement toward the stoker-inlet, and in which a dampervalve is provided to control the passage between the conduit and the stoker and is normally in a closed position, said damper-valve being connected for movement with the plate to open said passage when the reciprocatory plate is moved to provide a free-way for inflow of fuel to the stoker during such movement and to move reversely with the plate to close to elimsaid conduit to and adjustable means arranged 

